Control means for modulator tubes



Aug. 13, 1929. w KUMMERER 1,724,668

CONTROL MEANS FOR MODULATOR TUB ES Filed Sept. 24, 1926 INVENTOR LHELM KUMMERER TTORNEY Patented Aug. 13, 1929.

UNITED STATES PATENT OFFICE.

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Application flledseptember 24, 1838, Serial No. 137,485, and in Germany October 1, 1925.

The present invention relates to a circuit arrangement for transmitter tubes of the kind used for the purposes of telephony and telegraphy. What is involved is a method adapted to impart a variable auxiliary grld potential or bias to a modulator tube which rately-controlled main transmitter tube.

The auxiliary transmitter is regeneratively coupled by means of coil a which is contained in the oscillation circuit, and coil 0 which is contained in the grid circuit, and

it controls the main transmitter through coil 1). In parallel with the grid condenser f of the main transmitter is the modulator tube 2. A potential is impressed upon the grld of the modulator tube by rectification .of high frequency energy derived from the auxiliary transmitter circuit by means of coil d.

In the drawing, a rectifier tube 9 is provided by which the radio frequency energy is rectified and the direct current potential is brought to a condenserinserted in the grid circuit of the modulator tube, and which has in parallel connection with it a resistance.

This arrangement offers the advantage that, in case of decrease of'radio frequency energy at the auxiliary sender there is also a decrease in the grid potential or bias upon the modulator tube, and such a proportion of grid bias or potential on tube e to the os- 40 cillatorvoltage is maintained that, if correct conditions are chosen,'the tube will work inside the optimum region of the working characteristic. Compared with rectification of low-frequency current, this scheme offers the further advantage that it is easy to apply tone frequencies to the tube.

Having described my invention, I claim: 1. A transmitter tube control comprising, a transmitter tube, a regenerative auxiliary transmitter tube coupled thereto, a modulating tube connected in the gridcircuit of said transmitter tube and coupled with said auxil ary and transmitter tubesthrough said couphng, a rectifying means between said modulator input circuit and the coupling to said transmitter tube's, said rectifying means being adapted to supply rectified energy from said transmitters to said'modulator-to control the bias thereof, said bias control of the modulator tube being adapted to cause so a proportionality at all times between the current strength in the transmitter and modulator tubes whereby under-modulation and over-modulation is eliminated.

2. A transmitter tubecontrol comprising 65 a transmitter tube, an auxiliary transmitter tube coupled thereto, a modulator tube associated with said first named transmitter tube, and rectifying means connected between said transmitters and said modulator for controlling the grid potential of said modulator tube, said potential control being adapted at all times to produce a modulated signal which is proportional to the current strength in said transmitter. 3. A transmitter tube control comprising, a transmitter tube, a modulator tube associated therewith, and a rectifying means associated with said modulator and coupled with said transmitter, said rectifier being so adapted to control the grid bias of' said modulator tube so that the modulation is controlled proportionally to the strength of oscillation insaid transmitter.

4. A transmitter tube control comprising, 35 a tube transmitter, an auxiliary transmitter coupled thereto, a modulating tube connected in the grid circuit of said transmitting tube, a rectifying means connected between the grid circuit of said modulator and said aux- 9o iliary transmitter, said rectifying means being adapted to rectify a portion of the high frequency potential of said auxiliary transmitting system and supply the said rectified potential to said modulator, whereby the grid potential of said modulator is at all times proportional to the radio frequency energy in said auxiliary transmitter.

5. A transmitting tube control system comprising, a tube transmitter, a regenerative' auxiliary transmitter coupled thereto, a modulator tube coupled with said tube transmitter, a rectifying means coupled jointly with saidauxiliary transmitter to T5 said tube transmitter whereby a fractional part of the energy of said auxiliary, transmitter is transferred to said rectifying means, and means for associating said rectifylng means 1n the grid circuit of said modulator tube for controlling the otential bias upon the grid electrode of saldmodulator tube proportionally to the strength of oscillatlons 1n saldauxiliary transmitter.

WILHELM KUMMERER/ 

